Merged in chrishamm's changes including OutputBuffer fix, changes to
Roland pin numbers, rr_configfile support in web server, and Roland and
inkjet pin numbers moved to Pins_duet.h
Merged in wrangellboy's http response changes for compatibility with
Edge browser
Other minor changes
Fixed issue with rare missing steps at the end of delta moves
Fix minor delta calibration issue
Fix issue with ADC crosstalk on Duet 0.8.5
Refactored RepRap and OutputBuffer classes in preparation for fixing the
OutputBuffer bugs